When assisting a ship which no longer is able to progress through the ice, e.g. as a result of an ice ridge, an ice breaker vessel has to maneuver in along side the ship, break through the ice ridge and turn in immediately in front of said ship. The maneuver resembles a close "overtake". Often the ice breaker vessel subsequently has to back up towards the ship that needs assistance, in order to transmit a tow line. Ice breaking vessels are normally equipped with two propellers and a steering rudder in the longitudinal direction of each shaft. During backing maneuvers, the rudders and propellers are especially vulnerable to the impact of broken ice. In order to reduce the stress on the rudders, ice breaker vessels normally are equipped with ice wedges, which are mounted at the bottom skin, in the longitudinal direction of each propeller shaft, behind the rudder. Damages on the rudders may be avoided by positioning the rudders in parallel with the centerline of the ship. The propellers will nevertheless be worn by contact with broken ice.